Patients with chronic disabling pain which has persisted despite usual medical and surgical therapy constitute a difficult therapeutic challenge for the clinician. The options for therapy in the past have consisted of psychotherapy, neural ablative procedures, and treatment with narcotics. The long run efficacy of these treatment modalities has been disappointing, which thus necessitates the development of other therapeutic options. The use of phenothiazines has been advocated as part of the treatment program for these patients based on anecodotal evidence that they promote pain relief. The phenothiazines may act specifically as analgesic agents in specific forms of pain, and may help decrease the suffering associated with pain in general by creating affective indifference to it. Aneodotal experience with several hundred patients with chronic pain at The Johns Hopkins Hospital has supported the contention that treatment with fluphenazine is helpful in the overall management of these patients. It is our purpose to perform controlled double blind studies of the efficacy and role of this drug in the treatment of chronic pain. The experimental technique developed for this purpose will provide the framework for future studies of other chemotherapeutic modalities in the treatment of chronic pain.